A decade or so ago, powdered detergents having a density higher than had previously been the case began to appear in the market place. The new higher density powders were packaged in cartons more suitable for the increased weight of product relative to previous powders. These cartons typically included single or parallel perforated lines of weakness which were unzipped to open the carton. Often a plastic scoop was included in the carton to enable the consumer to dispense measured amount of product neatly.
While the scoop has proved to be a convenient way to dispense powders, its inclusion in the package posses some difficulties for the manufacturer. For instance, it is necessary to fill the carton in such a way that the scoop is not buried in the powder. Otherwise, the consumer would need to paw through the powder to locate the scoop.
Prior to the decrease in the use of conventional powdered detergent cartons, which occurred with the arrival of the higher density powders, efforts were made to improve the pourability of powders from such cartons. Examples of these efforts may be found in Gunn et al., U.S. Pat. No. 4,732,315, Heinz et al., U.S. Pat. No. 4,990,200 and Giblin et al., U.S. Pat. No. 4,981,256. An issue with these plastic closures was the ability to adhere them efficiently and reliably to the cartons.
The present invention is directed to the discovery of a better way to adhere plastic closures to either conventional or high density detergent powder cartons. The invention comprises a closure having a base and a cover attached to a base. The base includes a debossment or trough on the side opposite the cover to facilitate attachment of the base to a container. Alternatively, the debossment or trough may be disposed on the surface of the carton to which the closure is being applied or on both the carton and on the closure. Typically the container will be a carton for powdered detergents or other consumer products such as the following pourable, powdered products: freshener, baby food, automatic dishwashing detergent powder and cocoa mix.
The closure will generally be made of a thermoplastic material. The debossment may be in numerous forms, such as a rectangle or a square or most preferably a rectangle or square where each line of the rectangle or square intersects another line on opposite ends and extends past each such intersection.
Generally the base and cover are attached at one of their ends to keep the base and cover closed. Typically one of the base and cover include an embossment and the other of the base and cover includes a debossment or opening dimensioned to receive the embossment when the closure is closed. The embossment and the corresponding debossment or opening may be in any of several shapes including a tear-drop, a shield or a horseshoe shape. A centered, rippled (corrugated) lift tab may be present in the cover to facilitate opening by the consumer. The attachment between the cover and the base may include a living hinge and so may be repeatedly opened and reclosed.
Some prior closures had a completely flat underside to the base, and during application hot melt had to be spread and flattened as much as possible. No matter how much pressure was applied, there still was a small gap between the closure and carton surfaces. Not only was the gap aesthetically unappealing, but the gap sometimes engaged other edges, causing jams and other manufacturing problems.
In its preferred embodiment, the present closure has the centered lift tab with ripples to facilitate lifting, it has extensions on both sides of the tab to provide a straight edge for machine handling and application, and it has the peripheral trough or debossment in the underside of the base to receive and xe2x80x9cconfinexe2x80x9d hot-melt adhesive to functional parameters. The trough profile is shaped for improved carton adhesion and optimum bead width for attachment to the paperboard carton without powder sifting and with minimal or no carton/closure gap.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following description of up the preferred embodiments.